O uso da Dextrose como fonte de carbono no desenvolvimento de bio-flocos e desempenho do camarão-branco (Litopenaeus vannamei) cultivado em sistema sem renovação de água

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The objective of the present study was to evaluate the effect of dextrose as carbon source in bio-flocs development, as well as, its contribution to water quality maintenance and performance of Litopenaeus vannamei juveniles reared in superintensive system without water exchange. They were used two treatments, dextrose and molasses, with four replicates each. The carbon addition was carried out maintaining a C:N ratio of 20:1 and a C:TA-N ratio of 6:1. The physical and chemical water parameters, as temperature, pH, salinity, dissolved oxygen and transparency (Secchi) were daily monitored. The shrimps growth was monitored through periodic biometries. At the end of experiment, the remaining shrimps in each tank were counted to determine the survival rate and the biomass produced in each treatment. The feed conversion rate was calculated through the weight gain and the amount of consumed feed. During the experiment, they were collected samples, every three days, to evaluate the concentrations of dissolved organic carbon, chlorophyll a, suspended solids, flocs volume, ammonia, nitrite, nitrate and phosphate. The microbial composition present in the water and in the microbial flocs was quantified and classified by groups. The water quality parameters were within the acceptable range for the species rearing. The water transparency seemed to influence the microbial community performance. It was verified that both treatments demonstrated same performance on ammonia control, although, bio-flocs formation has earlier occurred in molasses treatment. Although differences have occured in bio-flocs formation, during the first two experimental weeks, it was noted better shrimps performance in dextrose treatment, however, the high nitrite levels may have caused low survival rate and final weight in both treatments. The data obtained in this study suggest that the dextrose use, as carbon source, can provide better zootechnical indexes for the culture of Litopenaeus vannamei in super-intensive system without water exchange.

ASSUNTO(S)

aquicultura aquicultura nitrificação bio-floco camarão-branco carbono

ACESSO AO ARTIGO

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